# cabal check Warning: The following errors will cause portability problems on other environments: Warning: Invalid 'tested-with' version range: ghc ==6.10 && ==7.1. To indicate that you have tested a package with multiple different versions of the same compiler use multiple entries, for example 'tested-with: GHC==6.10.4, GHC==6.12.3' and not 'tested-with: GHC==6.10.4 && ==6.12.3'. Warning: Hackage would reject this package.